REPORTS OF EXPERIMENTS WITH DIFFERENT TOP-DRESSINGS. 81 



riment was not thought of till after the result of the second crop 

 was known. 



The object of these experiments, as stated in the beginning, is to 

 ascertain whether the form in which nitrogen is applied materially 

 alters its beneficial influence on the growth of rye-grass and 

 clover. 



There are so many disturbing influences, as of weather, state 

 of soil, &c, which may affect the result of these and all other 

 experiments, that it is unsafe to draw conclusions from them, 

 unless they are supported by similar results, from experiments 

 tried in different soils, in different years, and with different quan- 

 tities of the dressings. It is particularly the case with these 

 results, for some of them are contrary to those of previous expe- 

 riments. Therefore, only the conclusions which these particular 

 experiments on this soil suggest are given. 



They are as follows : — 



That undecomposed nitrogenous matter in a state of fine divi- 

 sion is readily decomposed in the soil, and made available for the 

 plant, and that in this undecomposed state it is of equal value 

 with ammonia salts or nitrates, in its ultimate results, though it 

 is not so quick in its action, and has not, therefore, such a stimu- 

 lating effect on the first crop. 



In the effects of the sulphate of ammonia and chloride of am- 

 monium there is considerable difference, the latter giving a 

 quarter of a ton more hay per acre than the former. The chlo- 

 ride gains its advantage in the first crop, as the second crops are 

 equal. It would appear, therefore, that the acid has played an 

 important part — the hydrochloric acid being, in this case, the 

 more valuable of the two acids. Whether this is from the soil 

 being deficient in chlorides, or whether from the chloride of 

 ammonium having greater powers of diffusion through the soil 

 than the sulphate, requires further attention. If the chloride of 

 ammonium is more valuable as a dressing than the sulphate of 

 ammonia, when applied in the quantities in which they were in 

 this case, — that is, 1 cwt. 105 lbs. of sulphate, against 1 cwt. 63 

 lbs. of the chloride, then what a much greater crop would the 

 chloride give, if 1 cwt. 105 lbs. were applied. Thus, if the chlo- 

 ride could be made at nearly the same cost as the sulphate, it 

 might be a valuable manure. 



The nitrate of ammonia has been very beneficial to the first 

 crop, standing third best in its results on that crop, but it appears 

 to have destroyed the ultimate vigour of the plant, as it has given 

 the worst second crop of any of the dressings. This is probably 

 owing to its being all spent on the first crop, as in the nitrate 

 of ammonia the whole manurial value is in the two sources of 

 nitrogen, while in the other dressings which have been used, 

 the acid alone, or the base alone, contains the same quantity of 



F 



